Originally Posted by DasFitzkrieg
Actually, the mixed damage potential of Lich Bane was a part of what made it so strong before. Having an additional 1.0 AP-scaling physical damage nuke whenever you spellcast was extremely powerful, particularly if enemies were stacking MR against you. Between that and the MR removal, Lich Bane definitely lost some utility in the transition to Season 3.
How often does MR stacking occur though, really?
Jungle itemizes for armor---bot lane and supports itemize for armor, and top lane itemizes for armor unless its' an AP top---that leaves pretty much the AP mid the only one who is going to itemize for MR against you.
Will it happen, eventually? Yes, but the stacking will be nowhere
near the level of armor stacking.
With a few exceptions, you'll be lucky to see over 130 MR in a match---over 200 armor, on the other paw is not, at all, uncommon.